Could a tiny earthquake that struck on March 10 have triggered the massive landslide near the town of Oso on March 22?
Snohomish County Emergency Management Director John Pennington raised that possibility at a press conference this morning. But the director of the Pacific Northwest Seismic Laboratory said he thinks it’s highly unlikely.
The quake measured 1.1 on the magnitude scale, said John Vidale. It’s difficult to precisely locate such small events, he added, but the epicenter seems to have been about 2.5 miles underground and about a mile northeast of the slope that failed in the slide.
“That earthquake wouldn’t have triggered anything,” Vidale said.
It’s even possible the seismic signal was caused not by a quake, but by the ground in the vicinity shifting before the slide, he added.